Gains from 70mm throttle bodies?

[JohnnyBravo]

I have a 98 GTS with the Roe SC, 8# pulley and water/**** injection.

I was just wondering if there is much hp or tq to be gained by switching to the 70mm throttle bodies?

Do you have to do any other modifications? Bigger diamter smooth tubes? Different airbox setup?

Thanks in advance,
JB

 

[Simms]

You will need 3" smooth tubes, and the Roe modified airbox (just the back half).

And prepare yourself for idle hang.

 

[JohnnyBravo]

Any other comments?

 

[STUGOTS]

From what I understand TB's will gain quite a bit on a blown car. Headers as well.

I'd go for it

 

[JohnnyBravo]

From what I understand TB's will gain quite a bit on a blown car. Headers as well.

I'd go for it

Thanks.

The car is getting exhaust work done tomorrow. After that, I'll probably pick up throttle bodies (along with the modified airfilter box and new smooth tubes) and probably 1.7 roller rockers. I'm hoping with a good tune on the VEC 2 that the car will make 600 rwhp/650 tq on pump gas.

 

[Bob D]

My GTS is similar to yours except I have a 10# pully and Jesel rockers. With 70mm TB's I dynoed 668.7 hp/ 722.5 tq. Just for the fun of it I installed the stock TB's and dynoed 665.3 hp/ 726.4 tq. Not much difference but the throttle response is much better with the 70mm so I put them back on. With better flowing heads I think the 70mm's would make more of a difference.

Bob

 

[diabolos88]

not that much better, my setup is almost same as both yours. not much difference, imho TBs are total waste. you dont needem. spend good $ on heads.